The system parameters implemented in our experiment are listed in Table 1. The total number of pulses used in the experiment is \(10^{10}\) , and the failure probability \(\epsilon \)  is reasonably set as \(10^{-10}\) . The calculated optimal experimental parameters and the relevant data are displayed in Table 2. We conduct the experiment over 120 km and 150 km fibers, and achieve corresponding key rates as 43.54 bps and 0.06 bps respectively, which agrees well with theoretical predictions. Moreover, in order to illustrate the advantages of the new scheme, we also plot out the variation of the key rate with transmission distance by using either 3-intensity [1]} or 4-intensity [2]} decoy-state method, see Fig. 2. Obviously, the present double-scanning method shows overwhelming advantage compared with the other two schemes.
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